The present invention relates to a mechanism capable of making variation in radial angle. As being subject to a force, a component of the invention will swing to change in its radial angle, thereby making radial extension or retraction which result in expansion or reduction of area accordingly.
In most of the articles used in our domestic life, they often make use of fulcrums or pivots to effect the swinging motion thereof. For example, the closing and opening of a door or window having pivot joints, and the extension of a box or shade. All the motions, in addition to having fulcrums or pivots, are common in that the radii or areas of the articles in motion will remain unchanged during the motion.
As a particular article is subject to radial change with the radius and area thereof subject to uniform curvilinear extension or retraction simultaneously, further utilities may be achieved. For example, reduction in area as the article is closed may reduce the occupying space, increase in area as the article is extended will increase the acting area. Take the rowing action for example, if the acting surface of an oar is enlarged during the rowing stroke and reduced during the withdrawal stroke, the best possible effect will be attained.